1. Field of the Invention
The present invention relates to nanotechnology and to a nucleic acid based nano-robotic system.
2. Description of the Related Art
The laboratory of the present inventors has developed numerous techniques for building complex rigid structures out of DNA. In particular, double crossover (DX) (Li et al., 1996; Liu et al., 1999), triple crossover (TX) (LaBean et al., 2000), parallelogram (Mao et al., 1999a) and 6-tube molecules (Mathieu et al., 2001), all of which can form one and/or two dimensional repeating arrays were developed. In 1999, the laboratory of the present inventors reported the first DNA-based nanomechanical device (Mao et al., 1999b). It was based on the transition of known sequences of DNA to switch from right handed to left handed twists upon addition of a chemical actuator (Co(NH3)6+++) to the solution. Were one to put, say, 10 different versions of this device into a test-tube, one could still produce only two states, one with all the molecules twisted left, and another with all the molecules twisted right. In 2000, Yurke et al. developed a method for controlling numerous DNA nano-devices in the same test-tube independently. They managed this by making the control molecules DNA strands which hybridize with their complements, but no other molecules. Several groups including ours have produced DNA nano-devices on this theme (Yan et al., 2002; Simmel et al., 2001; Niemeyer et al., 2002). All the DNA nano-devices produced to date, however, have had two limitations. They only can enter a specific, finite, number of states; and those states are all essentially changes in shape of a single macromolecule.
A tremendous literature has arisen exploring numerous protein-based nano-motors (Hess et al., 2002; Soong et al., 2000; Allan et al., 2002). These have certain advantages over conventional DNA nano-devices. Being motors, they have an infinite range of motion (be it rotational or linear), and they consist of two portions—one large static molecule, and one smaller mobile molecule which moves along it. There are, however, disadvantages of protein nano-motors relative to DNA nano-devices. Protein motors only run in one direction, they are difficult to start/stop rapidly and precisely, and all such motors in a given environment will run whenever ATP fuel is made available (they lack the precise interface of DNA coded control strands).
Citation of any document herein is not intended as an admission that such document is pertinent prior art, or considered material to the patentability of any claim of the present application. Any statement as to content or a date of any document is based on the information available to applicant at the time of filing and does not constitute an admission as to the correctness of such a statement.